.nav {
  height: 41px;
  line-height: 37px;
  border-top: 3px solid rgb(247, 132, 0);
  border-bottom: 1px solid rgb(237, 238, 240);
  background-color: rgb(252, 252, 252);
}

.nav a {
  display: inline-block;
  height: 41px;
  font-size: 12px;
  color: rgb(72, 72, 72);
  text-decoration: none;
  /* padding：上下为0，左右是20px */
  padding: 0 20px;
}

.nav a:hover {
  background-color: #eee;
  color: rgb(247, 132, 0);
}